1. Field of the Invention
This invention relates to positioning structures on the edge of a sheet and, in particular, to securing edge members to a vehicle window in a manner that ensures proper overall sizing of the vehicle window.
2. Technical Considerations and Prior Art
Automotive windows are often provided with edge attachments or other various types of members secured along selected edges of the window. These members may be molded directly on the glass, e.g. as disclosed in U.S. Pat. Nos. 4,837,127 and 4,662,113 to Weaver. More specifically, the glass may be positioned in a mold system where the members are formed directly on and bonded to the marginal edge of the window. This type of operation, often referred to as encapsulation or reaction injection molding, is expensive and time-consuming. As an alternative, pre-formed members may be seated against the edge of the window and secured in place by an adhesive, e.g. as disclosed in U.S. Pat. Nos. 4,943,179 to Hiriki, et al. and 5,226,259 to Yamagata, et al. The problem faced with this type of arrangement is the accuracy and consistency of the overall dimensions of the window. More specifically, since the edge of the window is used as a guide for the edge member, if the edge dimension is incorrect, after the member has been secured to the window, the overall dimensions of the window will be incorrect. This may pose a problem when the member is used as a window guide, e.g. for a reciprocating door window, or requires precise positioning based on peripheral dimensions of the window, e.g. to seal the window against the vehicle body.
It would be advantageous to provide an arrangement for securing edge members to a vehicle window which ensures that the completed window assembly has the desired overall dimensions.
The present invention provides a fixture for positioning an edge member on a sheet. The fixture includes a base, an arrangement to locate a sheet to be supported on the fixture at a predetermined position relative to a plurality of datum points, and an arrangement to position an edge member to be secured along a peripheral edge of the sheet at a desired position relative to the datum points. In one particular embodiment of the invention, alignment stops are positioned to contact selected peripheral edges of the sheet while the sheet is supported on support posts to position and orient the sheet at a predetermined position relative to the datum points. The positioning arrangement may include a guide spaced from the peripheral edge of the sheet and placed at a predetermined location relative to the datum points such that edge members contacting the guide are at the desired position relative to the datum points.
The present invention also provides a method of mounting an edge member to a sheet, including the steps of establishing datum points, positioning a sheet relative to the datum points, and securing an edge member to a marginal edge of the sheet such that a base section of the edge member is spaced from a corresponding peripheral edge of the sheet and the edge member is at a desired position relative to the datum points. In one particular embodiment of the invention, stop members are located at the datum points, and the sheet is positioned by moving selected peripheral edges of the sheet into contact with the stop members and the edge members may be positioned at their desired position by locating the edge members on the sheet relative to a guide arrangement.
The present invention further provides window assembly comprised of a shaped glass sheet having a peripheral edge, and an edge member secured to the sheet along the peripheral edge, wherein the edge member includes at least one leg member extending along a portion of a major surface of the sheet and a base section spaced from the peripheral edge of the sheet.